FWIW: http://www.numberempire.com/equationsolver.php says -1/4. It will only give 11/3 if you explicitly put parentheses: (x-3)/(x-1)=(x-4)/(x-5) . So I believe Bing's result is correct. Based on elementary school order of operations, the implied parentheses on the original equation are: x - (3/x) - 1 = x - (4/x) - 5.